1. Field of the Invention
The present invention relates to methods and devices for measuring fundamental data of lenses for vision correction, such as eyeglass lenses or contact lenses, and general optical lenses. According to the present specification, the “fundamental data” means data relating to lens shape or lens material, which determine the optical properties (e.g., focal distance, refractive power) of the lens. Therefore, the fundamental data include data relating to the surface shape of the lens and the refractive index of the lens.
2. Description of the Related Art
Japanese Laid-open Patent Publication No. 5-231985 describes a lens meter for measuring the refractive power (i.e., focal distance) of a lens. This known lens meter has a lens stand. The lens to be inspected is placed on the lens stand and illuminated with a parallel luminous flux, and its refractive power is calculated by measuring the focal position after the light has passed through the lens.